With regard to a transmitter optical subassembly (TOSA) in an optical module, tracking error (TE) refers to a variation between the expected optical output power at different temperatures and the measured optical output power at a normal or ambient temperature with the optical output power at the normal or ambient temperature as a reference. TE also refers to a parameter for determining the stability of optical transmitter coupling efficiency in dB. TE is a vital indicator for the stability of the output optical power of the optical module. When the TOSA transmitting optical power is monitored by an optical module in operation, the accuracy of determining and/or detecting the TOSA transmitting optical power is lower than ideal because the operation temperature of the TOSA affects the TE, and thus, the stability of the output optical power.
This “Discussion of the Background” section is provided for background information only. The statements in this “Discussion of the Background” are not an admission that the subject matter disclosed in this “Discussion of the Background” section constitutes prior art to the present disclosure, and no part of this “Discussion of the Background” section may be used as an admission that any part of this application, including this “Discussion of the Background” section, constitutes prior art to the present disclosure.